The cash register broke down, so checkout took a long time.
checkout counter; cashier
Refers to the place where you pay, or the person operating the register. Common in retail and restaurant contexts.
レジでお金を払ってください。
Please pay at the checkout counter.
レジの人がとても親切だった。
The cashier was very kind.
There were a lot of people lined up at the checkout, so it took a bit of time.
Once you've chosen your items, please pay at the checkout.
I brought the clothes I'd chosen to the checkout.
The checkout is always busy in the evening.
operating a cash register; cashiering
self-checkout; automated checkout